1. Field of the Invention
This invention relates to semiconductor substrates used in the manufacture of various semiconductor devices for industrial and everyday use, and to semiconductor bare chips and semiconductor wafers on the surface whereof are formed integrated circuits, and more particularly to noise-suppressed electromagnetic wave absorbing semiconductor substrates and manufacturing method therefor, together with semiconductor devices manufactured using such semiconductor substrates.
The present invention also relates to an electromagnetic noise suppression body that exhibits outstanding high-frequency electromagnetic noise suppression effects, and more particularly to an electromagnetic noise suppression body that is effective in suppressing electromagnetic noise that is problematic in active devices that operate at high speeds or high-frequency electronic components and electronic equipment, and to a high-frequency electromagnetic noise suppression method using such body.
2. Description of the Related Art
The proliferation of highly integrated semiconductor devices that operate at high speed has been remarkable in recent years. Examples include the random access memory (RAM), read only memory (ROM), microprocessor (MPU), central processing unit (CPU), image processing arithmetic logic unit (IPALU), and other logic circuit devices. In these active devices, higher speeds are being achieved at a prodigious rate in terms of calculating speed and signal processing speed, and the electrical signals propagated through the high-speed electronic circuits have become a major cause of inductive and high-frequency noise because of the rapid voltage and current changes associated therewith.
Meanwhile, the trend toward lighter weight, thinner profile, and smaller size in electronic components and electronic equipment continues rapidly and unabatedly. In conjunction with that trend, the integration levels being achieved in semiconductor devices and the higher electronic component mounting densities being realized in printed wiring substrates are also remarkable. Accordingly, electronic devices and signal lines that are integrated or mounted overly densely become extremely close to each other, and the situation is now such that, in conjunction with the higher signal processing speeds being achieved, as remarked earlier, high-frequency spurious radiation noise is easily induced.
With conventional semiconductor substrates, no anti-noise measures are effected in the substrate itself. Therefore, when noise is generated from a semiconductor device circuit pattern region after the semiconductor device has been fabricated, noise leaks out to the outside as it is, and sometimes causes operating errors in other devices or equipment.
That being so, what has been done in terms of anti-noise measures for the semiconductor devices has been to apply an electromagnetic wave absorbing material to the back side of each individual semiconductor device, or something like that, to form an additional electromagnetic wave absorption layer.
With such conventional semiconductor device anti-noise measures as this, however, there is a problem in that the noise absorbing material, such as electromagnetic wave absorbing material, must be applied to the back side of each individual semiconductor device in a post-process, wherefore an enormous amount of time is required in the process to implement the anti-noise measure. Also, because they are applied to the back side of each individual semiconductor device, variation readily develops in the thickness of the noise absorbing members, such as electromagnetic wave absorbing material, and variation also develops in the noise absorption characteristics of the individual semiconductor devices, which also constitutes a problem.
As is commonly known, moreover, semiconductor bare chips that configure semiconductor devices, on the surface whereof are formed integrated circuits, are obtained by cutting semiconductor wafers that are semiconductor substrates.
Problems have been pointed out in connection with spurious radiation from power supply lines in such semiconductor bare chips, against which such measures as the insertion of decoupling capacitors or other concentrated constant components into the power lines have been implemented. Problems have also been pointed out in connection with spurious radiation from power supply lines going to active devices in electronic integrated devices and wiring substrates, against which such measures as the insertion of decoupling capacitors or other concentrated constant components into the power lines have been similarly implemented.
However, in semiconductor bare chips, electronic integrated devices and wiring substrates on the surfaces of which higher speed implementations integrated circuits are formed, the noise generated contains harmonic components, and therefore signal paths have come to exhibit a distributed constant behavior. As a result, situations have arisen where measures against noise that presume conventional concentrated constant circuits are ineffective.
Accordingly, there has been a need to develop electromagnetic noise suppression bodies that are effective in measures to suppress electromagnetic noise in such semiconductor devices and electronic circuits that operate at high speeds. More particularly, what has been needed is the development of electromagnetic noise suppression bodies capable of implementing measures against electromagnetic noise effectively with smaller volume.